The owner maintain their file on the server ,and removed from the system for space efficiency .the owner can burden of storing a large number of files from the owner to proxy server. The proxy server can convert encrypted files for owner to receiver without knowing the contents of original file. Issues like confidentiality , Integrity of the outsourced data must be addressed carefully In this scheme (a)The owner can decide the access permission without the help of private key generator. (b)For

more »

... ne query , the receiver can access only one file. (c)This scheme is against the collusion attack. In this scheme where an access permission is made by the owner for an exact file.